Hack a Day Links: April 27, 2011

At the Revision 2011 demo compo, a museum project called [MEGA] won first place in the “Wild” category with their zero bit recreation of “tennis for 2”. Entirely made of analog electronics, the retro game completes its presentation on a round o-scope screen. You can see a video of it after the break.

Mint-tin bicycle computer

[Alexdlp’s] newest instructable is a attractive and compact bicycle computer running off of an Arduino, and sports the usual bike features. It does not stop there, adding in a 16×2 LCD gives more room for data in both numeric form and bar graph form, and adding in a pair of radio modems allows that data to be fed back home where it can be logged and compared, perfect for the more serious biker.

8085 Reference Card

If you enjoy retro computers, or would like to make your own, you will find this Intel 8085 reference card is a real treat. Based on a original reference card, it has been expanded to give more detail for additional interrupts, electrical reference, T-State timing, and undocumented instructions.

6 thoughts on “Hack a Day Links: April 27, 2011”

Tennis for two is a bit of work. Originally running off of high voltage DC and tube op amps. This only complicates things because the op amps are single ended—no non-inverting inputs, which changes what circuit topologies are used (because you don’t have many op amps to waste, either). Another issue is that the original schematics, which were recently made available by Brookhaven National Lab, are full of errors. So that’s fun, too.

Other than the op amps, relays, and capacitors, the original had a handful of transistors. These may have been pricier, and were used to create the timing and display switching section (ie, it had to switch the output to the scope between drawing the net, drawing the floor, and drawing the ball). The first two were as simple as pairs of voltage-divided AC voltage and divided DC voltage and most of the circuit was for the third.
But this recreation looks pretty good!

The net bounce seems somewhat unreliable, but otherwise this is pretty awesome! When I worked on my own recreation, Peter Takacs from BNL was great in helping to point out a few of the errors/typos in the circuit (and to identify a circuit simple I’d never seen before–a floating variable dc supply! Looked like a two cell battery with an arrow pointing at it)